Vacuum Pumps

Industrial Vacuum Pumps

Single Stage Bare Shaft Liquid Ring Vacuum Pumps

Choosing the correct industrial vacuum pump for your application can be a difficult task. There are many different styles of pumps made and used for various processes and applications. Below you is a quick comparison chart of the pros and cons of various pump technologies.

For the reasons shown below, liquid ring pumps are the most frequently used vacuum pumps in the process industry. They are rugged, can be sealed with the process solvents from the process stream, and have very low maintenance requirements.

If there is not a condensable in the process stream suitable for sealing the liquid ring vacuum pump, or a lower operating pressure is desirable, or there simply is not cooling water available, an oil-sealed liquid ring pump is often a good option.

For applications where is absolutely no chance of condensation/process carryover or the pump can be protected adequately, a dry vacuum pump may be a suitable option.  Please note, however, that should these pumps ingest liquids and/or solids, and they become inoperable, repair costs are quite prohibitive.

Rotary vane pumps as indicated by the chart are much less expensive then the other vacuum pumps and ultimately less durable and thus are often used in less industrial applications.

Vacuum Pump TypeTypical
Ability to Handle
Process Carryover
Initial Capital CostMaintenance FrequencyRepair Difficulty
Liquid Ring Water or Solvent-Sealed> 30 Torr*HighCooling WaterMediumLowLow
Liquid Ring Oil-Sealed> 15 Torr*High
(Oil may get contamintated)
Dry Screw> 0.1 TorrLow to MediumSmall Amount of Water and Purge GasHighLowHigh
Oil-Lubricated Rotary Vane1 - 150 TorrLowNoneLowHighLow
Rotary Piston0.001 - 100 TorrMediumNoneLow to MediumMediumHigh

* Liquid Ring Operating Range can be extended down to 0.03 Torr with additional technology